Guaranteed Tournament are tournaments that have a Guaranteed prize pool, no matter how many entrants are in the tournament. Guaranteed tournaments have a buy-in and entry fee. Usually the prize pool is Guaranteed above the maximum number of players in the tournament, this ensures bigger prizes even if there are only a few tables competing.
There is big advantages to these tournaments. Alot of times the prize pools is double the buy-ins. This gives you a tremendous value.
Some Guaranteed tournaments have "rebuys" and "add-ons". This means that if you bust you can "re-buy" into the tournament and continue to play. An add-on is usually offered at the first break. Add-ons give those who are short stacked a chance to buy additional chips.
Below is a list of the upcoming guaranteed tournaments for US Poker Players.